In an unprecedented public condemnation of Pakistan, the chairman of the U.S. Joint Chiefs of Staff, Admiral Michael Mullen, has accused Pakistan's Inter-Services Intelligence (ISI) of actively supporting Haqqani network extremists whom he said target U.S. forces in Afghanistan.

He told lawmakers on the Senate Armed Services Committee that the Haqqani network “acts as a veritable arm of Pakistan's [Inter-Services Intelligence] agency.”

He also said it was “with ISI support” that Haqqani operatives attacked the U.S. Embassy in Kabul on September 13 and conducted a September 10 truck-bomb attack on a NATO outpost south of the Afghan capital.

That attack, which killed at least five people, also injured nearly 80 coalition troops, one of the worst injury tolls for foreign forces in a single episode during more than a decade of operations in the region.

"In choosing to use violent extremism as an instrument of policy, the government of Pakistan -- and most especially the Pakistani Army and ISI -- jeopardizes not only the prospect of our strategic partnership but Pakistan's opportunity to be a respected nation with legitimate regional influence," Mullen said.

Losing Bet

Mullen, who has for years led the U.S. military’s effort to improve cooperation with Pakistan, continued, saying, "[The government of Pakistan] may believe that, by using these proxies, they are hedging their bets or redressing what they feel is an imbalance in regional power, but in reality they have already lost that bet.

"By exporting violence, they have eroded their internal security and their position in the region. They have undermined their international credibility and threatened their economic well-being. Only a decision to break with this policy can pave the road to a positive future for Pakistan."

Speaking alongside Mullen, U.S. Secretary of Defense Leon Panetta said, “We’re going to do everything we have to do to defend our forces,” but declined to specify what operational steps his department might take.

He did say, however, that the Pakistanis would not likely “be surprised by the actions that we might or might not take.”

“The first order now is to put as much pressure on Pakistan as we can to deal with this issue,” he said.

"The Washington Post" reports that senior U.S. officials are prepared to consider an expansion of drone strikes in the region, as well as surgical ground strikes, if Pakistan is not willing or able to target the Haqqani network.

Mullen’s and Panetta’s statements came a day after a key U.S. Senate committee voted to make economic and security aid to Pakistan conditional on its cooperation in fighting militant groups, including the Haqqani network.

"The bill includes strengthened restrictions on assistance for Pakistan by conditioning all funds to the government of Pakistan on cooperation against the Haqqani Network, Al-Qaeda, and other terrorist organizations," a press statement by the Senate Appropriations Committee said on September 21.

The committee’s action still requires approval from the full Senate, and also needs to be reconciled with similar legislation in the House of Representatives.

Finger-Pointing

Meanwhile, in Kabul, senior Afghan officials are pointing the finger at the ISI for helping the Taliban to plan the September 20 assassination of former Afghan President Burhanuddin Rabbani.

Rabbani was the key figure responsible for negotiating with the Taliban. The insurgent movement said it is not commenting on Rabbani's murder.

Talking to reporters after a meeting with U.S. Federal Bureau of Investigation (FBI) Director Robert Mueller on September 21 in Islamabad, Malik said Pakistan was fighting the war on terrorism "as a frontline fighter" and the Pakistani government would not allow its soil to be used for terrorism anywhere in the world.

"As far as Haqqanis are concerned, we have discussed a number of issues. Yes, this is an irritant and we are resolving it together," Malik said. "And you know, Haqqanis are the production of the Soviet Union and Afghan war when we were partners and they are sons of the soil, but I assured [Mueller] they are not on the Pakistani side. But if there is any intelligence which is provided by the U.S., we will definitely take action."

Malik, however, changed his views a day later. In an interview with Reuters on September 22, Malik conceded that elements of the Haqqani network are based in Pakistan's North Waziristan tribal region on its western border with Afghanistan.

Observers say that the group can draw on a pool of roughly 10,000 to 15,000 fighters. Despite years of American pressure, Islamabad has resisted a large-scale offensive against militants in North Waziristan, something it has done in the rest of the tribal areas.

"Our capacity to trace them in that area is limited. Give us the information and we will operate," Malik said. "Let's have information. Let's have a proper investigation. And if there is a requirement, let's have an operation."

Malik said that Washington and Islamabad were fighting a common enemy without a joint strategy.

"Instead of a blame game, we have to sit together. We are not part of the terrorism. We are part of the solution," he said.